I have a 2000 S type 4.0 with 48K miles. Just recently I have had intermittent problems with the temp gauge rising to HOT and the check engine light comes on, after I turn off the a/c it slowly goes back to normal. I'll turn the a/c back on after a couple of minutes and then it is fine reading in the normal range. It happens about twice a week. It can run fine for a few days and then it happens again. The coolant level is fine, and I can find no leaks. I had it hooked up to a hand held computer at Autozone and it said PASS. There were no codes that came up.

The car never actually overheats but the gauge slowly rises to the red until I turn the a/c off, then the needle slowly drops back to normal. I live 60 miles from the nearest Jaguar dealership and I'm afraid to drive it more than an hour to have it checked out.

Has anyone had or know of this problem? Thanks, Nazz

 

Does your engine fan come on OK? In case you don't know - be very careful when checking as rotating machinery is dangerous (apologies if you do know).

You're right to be worried. And to be cautious about driving it. I'm not so sure how worried or cautious you should be but others will probably comment.

 

Bad thermostat

 

First if there is a check engine light go get the codes read at AutoZone. It's telling you what the problem is.

I would agree to change the thermostat AND the coolant. It's way over due!! Check that you don't have air trapped in the cooling system or that your degas bottle is cracked. Both common problems.

Also be aware that the car uses a hydraulic cooling fan. As this gets older they sometimes slow down and this reduces the air the fan can move.

Finally the CHT (Cylinder Head Temperature) sensor can also cause false overheating. Can you tell if the engine is really getting hot or not?

But first get the codes and post back on what you find.
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The actual message says HIGH ENGINE TEMPERATURE. When I had it tested at Autozone it said PASS. No codes were present.

I drove it again just about an hour ago around town with a/c going and the HIGH ENG TEMP came on again after 5 minutes with the needle in the red. I decided not to switch the a/c off as I felt that the car was actually not hot. After a couple of minutes the needle went back to normal and that was that. When the car said HET I noticed that the a/c had been blowing warmer and as soon as it leveled out (approx. 3 minutes) the a/c was cold as ice.

The fan comes on when I switch the a/c on and goes off when I switch it off. I noticed when I was stopped at a red light there was some fan noise and then 2 minutes later that's when it got hot. Not sure what that is.

 

Good trouble shooting!! If you can hear the fan noise increase that is good. Because that means the ECM has commanded the fan to increase it's speed due to engine temperature. The warm AC is again the computer adjusting things because it thinks the engine is over heating.

So I think you have a air bubble in the coolant. Have you added any coolant or done any service to the cooling system? Do you know how to bleed the air out of the cooling system? Close to the brake master cylinder you need to look for a hose that just ends and on the end it has a slot for a screw driver.
In the attached picture the hose should be to the left of the yellow brake cylinder cap.
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I agree

 

We are talking about the engine cooling fan and not the heater fan aren't we?

 

Hi, thanks for all the responses. Yes, we are talking about the engine cooling fan.

I have not added any coolant or done any service to the cooling system. I do not know how to bleed the air out of the cooling system, but I'm sure I can do it. Once I locate the hose then what?

On a side note: In my haste I went to pop off the plastic cover over the coolant reservoir and broke 2 plastic clips as they were very brittle. I tried to put them back but they won't hold. Does anyone know where I can find these? (See attachment)

Also, if I decide to replace the thermostat, it calls for coolant WSS-M97B44-D. Is DEX-COOL equivalent or should I not use?

 

The clips can be found at any Ford dealer. They are the same as the Lincoln LS and are used in the identical position. Remember to push down on the center to release the clip. Then when the clip is removed push the center piece back up where it's sticking above the surround. Then install the clip this way. Finally to seat the clip just push the center pin back down until it "snaps" in place. People break these by prying or pulling.

You don't need to remove that piece to add coolant? I guess you could if you wanted too but it is not necessary?

To bleed the air from the cooling system.
First get the engine up to temperature and then leave the car running. When you find the hose I talked about in the previous post with the slot for the screw driver. Just back out the slotted plastic piece until coolant comes out. If you have an air bubble it should whoosh out a bit before the fluid starts to come out. After doing it the first time you will be able to do it in seconds. Be aware that it usually is a good idea to bleed it several times over several days. Just to be sure!!
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Thanks for the tip tbird. I'll check with my Ford dealer for the clips. Any thought on the coolant? I was told not to use DEX-COOL.

 

change your thermostat, and the coolant is good for around 150,000 miles. or 10 years. i do believe. You should have the orange coolant right?
Prestone Orange long Life Antifreeze=14.99 for 1 gallon at Pep Boys is what i used

 

Be sure and use the correct coolant. Jaguar made a change and I don't remember what year it was. My 2005 STR does use the orange color Dex-cool. But just read the coolant jug and make sure the spec you posted (WSS-M97B44-D) is on the jug. If it is not then it is not the correct coolant. I think this is the same as my wife’s 2003 Lincoln LS. I had some problem finding this but you can always go any Ford dealer to get the correct fluids.

I don't let my coolant or oil go as long as the factory says. I do my own service so I change the oil about every 7K miles and coolant is changed at least every 4 years. I will have the transmission serviced by the dealer as it is a bit much for a shade tree mechanic!! I already have changed the P/S fluid but got the squeaking steering fixed with the additive and will not mess with from now on.
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Thanks for the input guys. I think I'll just go ahead and change the thermostat and put in the Prestone Orange Long Life Antifreeze. I just went to Advance Auto Parts and they had it - $13.99. I read the label and it said it meets WSS-M97B44-D which is what my 2000 S-Type calls for.

I am a bit skeptical of the thermostat from the auto parts stores. I saw an OEM Jaguar thermostat on eBay for less than $50. Do you think I'll be OK with the "off the shelf brand" for around $15.99?

I figure for around $30 - $65 DIY opposed to $400 that the dealer wants is money well spent even if it doesn't fix my HET problem.

 

my thermostat was 13.99 at pep boys...........seems to be the same thing i took out of mine. And it was the one that came with the car. stant makes them on an OEM level also from what i was told

 

OK... Finally changed out the thermostat. It's been raining here every day for the past week. I needed to do it outside so I finally saw the sun and went for it. It was actually easier than I thought. After I buttoned it back up I took it for a spin and found no leaks. Had to add a bit more fluid and topped it off. Went for another spin and within 2 minutes the gauge crept up to HOT and the Hot Engine Temp warning came on. Turned off the a/c and slowly the gauge went back to normal. I turned the a/c back on and it ran normal for ten minutes until I came back home and parked it. Checked the fluid level and it was good. No leaks from underneath.

So now I am back to square one. At least it only cost me around $35 bucks compared to the dealers $400 to change the thermostat and fluid. But now I still don't know what is wrong. The fan seems to be working properly as it sat idling in the driveway for about 10 minutes the cooling fan came on.

Any suggestions?

 

You may have a blown head gasket Nazz. The 4.0 will blow the gaskets if overheated. We have no idea how hot the engine has actually got, but if you changed the thermostat, and she still overheats, I'd have that checked. If that gauge has hit the red, she's overheated. That's why it's red over there, and also why you got the message of high temperature. I've rarely seen a clogged radiator, especially low mileage cars.

Also the 4.0 DOES NOT have a cylinder head temp sensor, only the 3.0L has that. The 4.0 uses a temp sensor located in the bypass pipe assy for ECM feedback during warm up and running, and also it is used for engine temp transmitted to the gauge.

One more thing, these things are a pain to bleed the air out of. I use a coolant system vacuum bleeder/coolant filler on these beasts. It is hooked to the coolant reservoir, then air is supplied to the mechanism, by hitting the button on the unit, it uses a venturi effect to suck out the air from the system. You will see the hoses collapse as air is removed putting the system in a vacuum. Then hook the other "fill" hose into a fresh gallon of coolant/water mix, turn valve and watch the show......coolant being sucked into your cooling system. Very good tool, and can be had at most good tool depots. Snap On, Matco, and Mac tools all make them, and you can order them on their websites. A must if you ask me. And they can be used on any car.

 

did you bleed the coolant system afterwards??????

 

I opened the slotted plastic piece on the tube when the engine got up to temperature. Coolant was coming out and I screwed it back in. I'm either doing something wrong or I need to get a vacuum bleeder/coolant filler that poboy was talking about.

 

I was reading in another post where the coolant system is temperamental and it sometimes takes 2-3 days to totally bleed or burp the system. So I decided to try it again. I let the car get up to normal operating temperature with the a/c blowing and opened the valve and I could see where a bit of air escaped before the coolant started to drip.

If I only re-read tbird6 saying... "Be aware that it usually is a good idea to bleed it several times over several days. Just to be sure!!"

That was the trick. No more overheating. I let the car sit idling in the driveway for about 15 minutes. Then I took it for a spin around town for another half hour and the temp gauge never moved from its normal straight up and down position.Thanks to everyone for their input. Problem solved.